DE3018160C2 - Chassis for folding stroller - Google Patents

Description

The invention relates to a chassis for folding strollers with two side parts which are connected to one another by foldable cross struts and which can each be folded into themselves, each consisting of a front wheel strut which points forwards and downwards in the position of use, a rear wheel strut which points backwards and downwards, a push bar which is provided with a foldable handle and points backwards and upwards, an angle rail which is pivotably and lockably articulated at one end to the lower end of the push bar and at its other end to the central section of the rear wheel strut, an upper connecting rod which articulates the central section of the push bar to the upper ends of the front wheel strut and the rear wheel strut, and a lower connecting rod which articulates a section of the angle rail which is spaced apart from the joint with the rear wheel strut to the central section of the front wheel strut.

Such a folding stroller is known, for example, from DE-OS 24 54 557. In this case, the folding process is triggered using an angle rail, which is pivotally connected at one end to the rear wheel strut and at the other end to the push rod, and on which another cross strut is pivotally mounted, which extends forwards to the front wheel strut and is also pivotally arranged there. If the push rods are pressed downwards, the angle rail pivots backwards around the lower hinge point with the rear wheel strut, which ultimately moves the push rods, the front wheel and the rear wheel struts towards each other so that they finally assume the position shown in DE-OS 24 54 557 in Fig. 3.

In this folding carriage, however, two articulation points are provided for each of the cross struts extending between the pairs of struts, which are designed in such a way that the side frames, as can be seen quite clearly in particular from Fig. 8, can be folded together around these articulation points, like the covers of a book, after which the central parts of the cross struts then form the spine of the book.

Folding up this well-known stroller requires a series of operations, so that handling such a folding stroller is still relatively complex. The large number of joints in the middle area of the connecting rods or crossbars results in a relatively wobbly structure overall. The design of the folding mechanism also means that in the folded position the front wheels are higher than the rear wheels, so that the folded stroller itself cannot stand upright and must always be leaned against something to prevent it from tipping over.

Based on this prior art, the object of the present invention is to provide a stroller in which the folding process is simplified, which can be folded with just one hand and which is stable even when folded.

According to the invention, this object is achieved in that a central cross strut which can be folded forwards in the middle in the position of use is articulated to the middle section of the two lower connecting rods, to which a pair of tension rods engages without joints at a distance from their middle, which extend in a V-shape to the middle of a rear cross strut which is articulated to the rear wheel struts near the edge and can be folded downwards in the middle in the position of use and there engages there in an articulated manner.

This folding mechanism of the stroller according to the invention has the advantage over the above-mentioned prior art that it can be pivoted by the pivoting arrangement of the front and rear wheel struts on the connecting rods by means of common pivot pins and by the curved design of the upper end of the front wheel struts in cooperation with a pair of drawbars which extend between the two foldable crossbars and are articulated to them, it can be folded up with just one hand into a position in which it is only reduced in its height, width and length, the front and rear wheels still being arranged at the same height when folded up, so that the folding stroller is stable even in this state.

The components of the chassis for folding strollers according to the invention and their interaction are explained in more detail below using a preferred embodiment as an example.

Show it:

Fig. 1: a perspective view of a trolley according to the invention in the unfolded state;

Fig. 2: a view of the state shown in Fig. 1;

Fig. 3: a view of the carriage shown in Fig. 1 in the closed state from the right side;

Fig. 4: a perspective view of portions of a connecting rod, a front wheel stay and a connecting rod for the front wheel stay according to Figs. 1 and 2, seen from the rear;

Fig. 5 and 6: Schematic view for explaining the movement mechanism of the components shown in Fig. 4;

Fig. 7: a perspective view of the sections of a cross brace for the rear wheel struts and a cross brace according to Figs. 1 and 2, seen from the rear;

Fig. 8 and 9: perspective schematic view to explain the movement mechanism of the components shown in Fig. 7 and

Fig. 10: a schematic view for further explanation of the representation according to Fig. 9.

Fig. 1 includes a perspective view of a stroller according to the invention in the unfolded state. A view from the right side of the stroller, but in the folded state, is shown in Fig. 3. Basically, the stroller comprises a pair of front wheel struts 3 , a pair of rear wheel struts 4 , a pair of push rods 13 and a pair of rods 1 connecting the struts and push rods. The rear wheel struts 4 are pivotally mounted on pivot pins 2 in a relatively front or middle region of the connecting rods 1. A pair of pusher struts 6 are pivotally mounted on pivot pins 5 associated with the push rods, which are arranged at the rear ends of the connecting rods 1 at a predetermined distance from the lower end. The stroller further comprises a cross brace 8 for the front wheel braces, which can only be folded down in the direction shown by the arrows 7 , a cross brace 10 connecting the rear wheel braces 4 , which can only be folded in the direction shown by the arrows 9 , and a handle bar 12 for connecting the pusher braces 6 , which can only be folded in the direction shown by the arrows 11. The pusher braces 6 and the handle bar 12 form the push bar 13 .

In such a basic structure, the lower ends of the pusher struts 6 and the rear wheel struts 4 are foldably connected to one another by angle rails 14 via pivot pins 15 and 16 , so that the lower ends of the pusher struts 6 are arranged either above or below the rear wheel struts 4 depending on whether the angle rails 14 are rotated to extend along the upper halves of the rear wheel struts 4 ( Figs. 1 and 2) or after rotation in the direction of arrow 17 along the lower halves of the rear wheel struts 4 ( Fig. 2). When the lower ends of the pusher struts 6 are arranged above the rear wheel struts 4 , the connecting rods 1 , the lower portions of the pusher struts 6 and the upper portions of the rear wheel struts 4 define triangles, and the stroller is then in the unfolded state. The structure and shape of the relevant components are selected such that the connecting rods 1 , the push bar struts 6 and the rear wheel struts 4 are substantially parallel to one another when the lower ends of the push bar struts 6 are arranged below relative to the rear wheel struts 4 , which means that the stroller is in the folded state.

A connecting rod 18, which is actuated during folding, is arranged between the associated angle rail 14 and the front wheel strut 3 and is pivotally connected to these at their opposite ends by pivot pins 15 and 19. A cross strut 21 , which can only be folded forward in the direction of arrow 20, is arranged between the pair of connecting rods 18. This completely characterizes the basic structure of the collapsible stroller.

The different components are described in detail below.

Fig. 4 shows a perspective view of the operatively connected portions of the connecting rod 1 , front wheel strut 3 and cross strut 8 , seen from behind. Figs. 5 and 6 show schematic views for explaining the movement mechanism of the components shown in Fig. 4. With reference to Figs. 1 to 6, the cross strut 8 is connected at its ends by pivot pins 22 to sliders 23 for the cross strut 8. Each slider 23 is provided with a bushing portion 24 with an inverted U-shaped cross section, which is placed on the top of an end portion of the cross strut 8 to cover this end portion. The slider 23 is arranged on the associated front wheel strut 3 in the middle region thereof in the axial direction. A hinge rod 25 is arranged between the slider 23 and the front end of the connecting rod 1 . An L-shaped arm extends inwardly from the front wheel strut 3 and is pivotally connected thereto by a pivot pin 26a . The cross strut 8 is pivotally mounted on pins 27 , each of which is mounted at the front end of the associated arm 26 and arranged at a predetermined distance from the associated end of the cross strut 8 .

In the arrangement described above with reference to Fig. 4 and other figures, if the connecting rod 1 is rotated about the axis of the pivot pin 2 in the direction of the arrow 28 , the slider 23 slides on the front wheel strut 3 in the direction of the arrow 29. As a result, the arm 26 is rotated in the direction of the arrow 26b , whereas the cross strut 8 is rotated about the axes of the pivot pins 27 in the direction of the arrows 7 and is thereby folded downwards ( Fig. 6).

The reverse movement of the cross member 8 of Fig. 6 from its folded position is effected by rotation of the connecting rod 1 in the opposite direction, whereby the link rod 25 depresses the slider 23. The force exerted by this movement rotates the cross member 8 from the position shown in Fig. 6 to the extended position, moving the arm 26 downwards and thereby achieving the condition shown in Fig. 5.

When the crossbar 8 is in its extended state shown in Fig. 5 and other figures, i.e. when the stroller is unfolded, the application of a downward force to the connecting rod 1 (for example the weight of an infant sitting in a chair attached to the connecting rods 1 ) causes the link rod 25 to press the slider 23 downward in the direction opposite to the direction of the arrow 29 , thereby pressing the end portion of the crossbar 8 for the front wheel brace which is received in the socket portion of the slider 23 downward and thereby bending the crossbar 8 upward. This, through the action of the arms 26, prevents rotation of the crossbar 8 in the direction of the arrows 7. That is, the greater the amount of load applied, the more strongly the stroller is held in its unfolded state.

Fig. 7 shows a perspective view of the operatively connected sections of the cross brace 10 for the rear struts, seen from the rear. Figs. 8 and 9 contain perspective schematic views for explaining the movement of the sections shown in Fig. 7. Fig. 10 shows a schematic view (viewed from one side) showing the bearing relationship between a connecting rod 18 , the cross brace 21 and the tension rods 30 shown in Fig. 9.

Referring to Figs. 1 to 3 and 7 to 10, the cross bar 21 is arranged at a different height from that of the cross bars 10 for the rear wheel struts. The selected folding direction of the cross bar 21 in the direction of the arrows 20 is not such that the bar is folded in a plane containing the pair of connecting rods 18 , but that the folding operation takes place in a direction slightly upwards relative to the plane containing the connecting rods 18. This type of folding is best seen in Figs. 3, 9 and 10. A pair of tie rods 30 are provided so that the folding operation of the cross bar 21 in the direction of the arrows 20 takes place together with the folding operation of the cross bar 10 for the rear wheel struts in the direction of the arrows 9 . The tie rods 30 are connected at one end to the folding section of the cross brace 10 and at their other end to opposite sides of the folding section of the cross brace 21 and at predetermined sections of the folding section. The cross brace 21 has tongues 33 which each extend laterally from a rotatable bush. Thus, the tie rods 30 are connected at one end to the tongues 33 .

The structure described with reference to Fig. 7 and other figures is such that the crossbar 10 and the crossbar 21 move against each other during the folding operation of the crossbar 10 in the direction of the arrows 9 (downward) and the pair of connecting rods 18 move against each other due to other components, so that the pair of tie rods, each of which moves in the direction of the arrow 34 , folds the crossbar 21 in the direction of the arrow 20 , i.e. forward.

It is important to note the dependent movement of the rear cross member 10 , the middle cross member 21 and the tie rod 30. That is, when the connecting rods 18 move towards each other, the cross member 10 and the cross member 21 are folded outwards, namely in the direction of the arrows 9 and 20 respectively, simply by the supporting action of the tie rods 30. However, another movement also takes place which must be noted. That is, due to the folding action of the cross member 21 in the direction of the arrows 20, the pair of pins 31 , bushings 32 and tongues 33 move against each other. This causes the tie rods 30 to rotate in the direction of the arrow 34 . If the tie rods 30 are not arranged in a V-shape but parallel to each other, the crossbars 10 and 21 could only be folded to the extent corresponding to the amount of relative movement of the crossbar 10 and the crossbar 21 with respect to each other. In contrast, the V-shaped arrangement of the tie rods 30 shown in Fig. 7 and other figures allows the crossbars 10 and 21 to be folded to the extent corresponding to the amount of relative movement of the crossbar 10 and the crossbar 21 with respect to each other plus the amount of pivoting of the tie rods 30 in the direction of arrow 34. Thus, this arrangement achieves a greater folding of the crossbar 10 and the crossbar 21 so that the width of the collapsible stroller can be reduced in the folded state. In addition, the mechanism for carrying out the operations described above is extremely simple. The reversing operation is carried out in the same way due to the coupling provided by the tie rods 30 .

From the above description it will be seen that the arrangement in which the folding direction of the cross-member 21 is chosen to be directed slightly upwards from the plane containing the connecting rods 18 is intended to ensure that during the folding movement of the cross-member 10 and the cross-member 21, the plane containing the cross-member 21 in its folded state coincides, at least for a moment, with the plane containing the pair of tie rods 30 or intersects therewith at a very small angle A ( Fig. 10). This coincidence of direction means that the plane in which the tie rods 30 act coincides with the plane in which the cross-member 21 is folded, thereby causing an effective transmission of the forces exerted by the tie rods 30 to the cross-member 21 .

In the embodiment described, this period of directional coincidence is almost reached when the crossbar 21 is close to its maximum folded state. That is, the collapse takes place when the folding operation of the stroller is almost complete. This is related to the folding operation of the stroller described later and takes into account that in the initial stage of the folding operation, when the stroller is unfolded from its closed position to the unfolded position, and in the final stage, when the unfolded stroller is folded, the person carrying out the folding operation feels resistance to exerting a greater force or a greater force is required. In particular, the folding stroller can be folded by pressing the push rod 13 downwards against the ground in such a way that the angle rails 14 rotate in the direction of arrow 17 ( Figs. 1 and 2), whereas when the stroller is opened, the push rod 13 is raised in order to utilize the weight of the stroller for the further progress of the folding operation. In this case, there is a limit to the weight of the stroller, so that the stroller is constructed to be lightweight.

Therefore, such a large force cannot be applied during folding operation. For this reason, the cross member 21 can be rotated with a small force in the initial stage of the transition from the folded to the unfolded state ( Figs. 3 and 9), when the direction of action of the tie rods almost coincides with the folding direction of the cross member 21. Finally, in the final stage of the transition from the unfolded to the folded state, a relatively large force is required to cause the components to assume the position shown in Fig. 3. In this respect, the embodiment described above is therefore very advantageous.

The structure of the stroller according to an embodiment of the invention is now described in detail as it relates to the folding operation.

From Fig. 1 and 2, which show the stroller in the unfolded state, it can be seen that the angle rails 14 follow the upper halves of the rear wheel strut 4 when rotated, so that the lower sections of the push bar strut 6 are arranged relatively above the rear wheel strut 4. At the same time, a triangle is created which results in the unfolded position of the stroller, which is determined by the connecting rod 1 , the lower section of the push bar strut 6 and the upper section of the rear wheel strut 4 .

The folding process of the stroller from the position shown in Fig. 1 and 2 to the position shown in Fig. 3 is described in more detail below. First, the operating lever 78 is pivoted until it is brought into an upper, pivoted position. Furthermore, the pressure contact between the bushing 44 and the angle rail 14 is eliminated. The process described so far can be carried out by successive manipulation of the two operating levers 78 with one hand. Next, one side of the central folding section of the handle bar 12 is grasped with one hand and the push rod 13 is tilted slightly forward by applying a rotating force in the direction of the arrows 11 so that the angle rails 14 are rotated slightly in the direction of the arrow 17. Finally, the push rod 13 is pushed downwards by the hand which has grasped the handle bar 12. When this pushing process is carried out, at least the rear wheels 72 interact with the ground.

In addition, there are cases where the rotational force acting on the handle bar 12 in the direction of the arrows 11 and the initial torque acting on the angle rails 14 in the direction of the arrow 17 are automatically generated by the weight of the stroller. In particular, if the person operating the stroller grasps the handle bar 12 at one side of its central folding portion with one hand and tilts the entire stroller backwards such that the front wheels 71 are suspended in the air while the rear wheels 72 are in contact with the ground, the weight of the stroller acts to cause the other side of the handle bar 12 to sag through the center or central folding portion. In this way, a rotational force acting on the handle bar 12 in the direction of the arrows 11 is generated. Finally, the angle rails 14 and the slider bar 6 are folded down under gravity. Thus, a force is generated which acts on each angle rail 14 and rotates it in the direction of the arrow 17 . After folding the handle bar 12 and rotating the angle rails 14 to a certain extent under the two types of forces described, the person operating the stroller swings the stroller back to its original position and pushes the push bar 13 downwards by the hand grasping the handle bar 12. This causes the process described below.

The angle rails 14 are rotated further in the direction of the arrows 17 until they extend along the lower halves of the rear wheel struts 4. This causes the connecting rods 1 to rotate substantially about the axes of the pivot pins 2 in the direction of the arrow 28 , whereby the link rods 25 move the sliders 23 in the direction of the arrow 29. This causes the cross bar 8 to fold in the direction of the arrow 7. This folding of the cross bar 8 cooperates with the folding of the handle bar 12 described above, so that the width of the stroller is reduced. This simultaneously folds the cross bar 10 for the front wheel strut in the direction of the arrows 9 , which causes the tension rods 30 to fold the cross bar 21 in the direction of the arrows 20 . Furthermore, due to the pivoting of the angle rails 14 in the direction of the arrow 17, the connecting rods 18 pull the front wheel struts 3 against the rear wheel struts 4. These folding operations take place substantially simultaneously until the angle rails 14 are in a position in which they extend along the lower halves of the rear wheel struts 4. At this time, the front and rear wheel struts 3 and 4 are folded together such that they extend substantially parallel to each other and the connecting rods 1 are rotated in the direction of the arrow 28 to receive the struts 4 in the interiors of the connecting rods 1 , so that finally the connecting rods and the rear wheel struts 4 are in substantially parallel positions. Finally, the crossbar 8 for the front wheel strut, the crossbar 10 for the rear wheel strut, the handle bar 12 for the push bar and the respective pairs of connecting rods 1 , front wheel struts 3 , rear wheel struts 4 , pusher struts 6 , handle bars 12 and connecting rods 18 are moved towards each other until they are close together and the stroller is also folded in terms of width. In this folding position, the two front wheels 71 and the two rear wheels 72 are all at the same height so that the stroller can be parked.

When the stroller is to be moved from the folded position shown in Fig. 3 to the unfolded position shown in Fig. 1, the above-described steps need only be reversed, whereby the reverse operation takes place. In brief, the person operating the stroller holds the handle bar 12 with one hand and lifts it to raise the stroller in the air so that the pusher bars 6 rotate the angle rails 14 in the anti-clockwise direction shown in Fig. 3. This results in the angle rails 14 extending along the upper half of the rear wheel bars 4 and the connecting bars 1 being rotated in the anti-clockwise direction so that the pivot bars 25 and sliders 23 straighten the cross bar 8 for the front wheel bars. Finally, the connecting bars 18 move the front wheel bars 3 away from the rear wheel bars. 4. Due to the resulting increase in width, the crossbar 10 and the crossbar 21 are straightened as a result of the coupling via the pull rods 30. As soon as the state shown in Fig. 1 and 2 is fully achieved, the operating levers 78 are pivoted downwards so that a safety device (not shown) prevents the handle bar from folding, while the bushings 44 are brought into pressure contact with the angle rails 14 so that the angle rails 14 and push rod 13 are prevented from folding and the stroller is held securely in its unfolded position.

The shape of the entire stroller is evident from Fig. 1 to 3. Only Fig. 2 shows the outline of a child seat. This seat comprises a backrest 150 which is supported by support rods 106 and a seat 151 formed on a plane which is formed by the connecting rods 18 and the crossbar 21. In this case, the connecting rods 1 serve as armrests. In addition, side supports 152 are arranged vertically on opposite sides of the backrest 150 according to Fig. 2 (the backrest 150 is not clearly visible in Fig. 2). Finally, an adjustment mechanism is provided in the child seat in order to be able to adjust the angle of inclination of the backrest 150 .

Claims (4)

1. Chassis for a folding stroller, with two side parts connected to one another by foldable cross struts, each of which can be folded into itself, each of which consists of a front wheel strut pointing downwards to the front in the position of use, a rear wheel strut pointing downwards to the rear, a push bar provided with a foldable handle bar and pointing upwards to the rear, an angle rail which can be pivoted and locked at one end to the lower end of the push bar and pivoted at its other end to the middle section of the rear wheel strut, an upper connecting rod which articulates the middle section of the push bar to the upper ends of the front wheel strut and the rear wheel strut, and a lower connecting rod which articulates a section of the angle rail which is spaced apart from the joint with the rear wheel strut to the middle section of the front wheel strut, characterized in that on the middle section of the two lower connecting rods ( 18 ) there is a middle cross strut ( 21) which can be folded forwards in the middle in the position of use. ) is articulated to which a pair of tie rods ( 30 ) are articulated at a distance from their centre, which extend in a V-shape to the centre of a rear cross strut ( 10 ) which is articulated to the rear wheel struts ( 4 ) near the wheel and can be folded downwards in its centre in the position of use, and there engage therein in an articulated manner. 2. Chassis according to claim 1, characterized in that an articulated rod ( 25 ) is articulated to each upper connecting rod ( 1 ), which, when the frame is folded up, causes a synchronous folding of a front cross strut ( 8 ) which can be folded in its center in the plane of the front wheel struts ( 3 ) between them. 3. Chassis according to claim 2, characterized in that each articulated rod ( 25 ) is articulated to a sliding piece ( 23 ) which is displaceable on the associated front wheel strut ( 3 ) in the longitudinal direction thereof, to which the front cross strut ( 8 ) is articulated, to which in turn an arm ( 26 ) is articulated at a distance therefrom on at least one side, the other end of which is directly articulated to the associated front wheel strut ( 3 ). 4. Chassis according to claim 3, characterized in that each upper connecting rod ( 1 ) is extended forwards beyond the articulated connection ( 2 ) with the front wheel strut ( 3 ) and the rear wheel strut ( 4 ) and the associated articulated rod ( 25 ) engages this extension, so that the front cross strut ( 8 ) is folded downwards when the frame is folded together.